Myasthenic patients who initially present in a stable fashion with normal ventilation and minimal dyspnea can decompensate rapidly.
In Myasthenia Gravis, the body produces antibodies against native post-synaptic acetylcholine (Ach) receptors. Adding a paralytic that occupies the few remaining functional Ach receptors could significantly prolong general muscular dysfunction and the need for ventilatory support during a myasthenic crisis.
If intubation is required, DO NOT administer neuromuscular blocking/paralytic agents such as succinylcholine or rocuronium, as these agents antagonize Ach binding receptors at the post-synaptic membrane of the neuromuscular junction.
Studies have shown that the use of propofol and fentanyl, without any paralytic, provides sufficient analgesia and sedation to successfully complete a humane intubation in these cases.
References
Narimatsu E, et al. Tracheal intubation without neuromuscular relaxants for thymectomy in myasthenic patients. Journal of Med. 2003; 34 (1-6): 47-48.
Vlajkovic G, et al. Endotracheal intubation without the use of muscle relaxants in patients with myasthenia gravis. Med Pregl. 2009 Sep-Oct; 62 (9-10): 412-416.
